Module documentation for 0.5.0.1

store

The ‘store’ package provides efficient binary serialization. There are a couple
features that particularly distinguish it from most prior Haskell serialization
libraries:

Its primary goal is speed. By default, direct machine representations are used
for things like numeric values (Int, Double, Word32, etc) and buffers
(Text, ByteString, Vector, etc). This means that much of serialization
uses the equivalent of memcpy.

We have plans for supporting architecture independent serialization - see
#36 and
#31. This plan makes little endian
the default, so that the most common endianness has no overhead.

Instead of implementing lazy serialization / deserialization involving
multiple input / output buffers, peek and poke always work with a single
buffer. This buffer is allocated by asking the value for its size before
encoding. This simplifies the encoding logic, and allows for highly optimized
tight loops.

store can optimize size computations by knowing when some types always
use the same number of bytes. This allows us to compute the byte size of a
Vector Int32 by just doing length v * 4.

It also features:

Optimized serialization instances for many types from base, vector,
bytestring, text, containers, time, template-haskell, and more.

Blog posts

Changes

ChangeLog

0.5.0.1

Updates to test-suite enabling store to build with newer dependencies.

0.5.0

Data.Store.Streaming moved to a separate package, store-streaming.

0.4.3.2

Buildable with GHC 8.2

Fix to haddock formatting of Data.Store.TH code example

0.4.3.1

Fixed compilation on GHC 7.8

0.4.3

Less aggressive inlining, resulting in faster compilation / simplifier
not running out of ticks

0.4.2

Fixed testsuite

0.4.1

Breaking change in the encoding of Map / Set / IntMap / IntSet,
to use ascending key order. Attempting to decode data written by
prior versions of store (and vice versa) will almost always fail
with a decent error message. If you’re unlucky enough to have a
collision in the data with a random Word32 magic number, then the
error may not be so clear, or in extremely rare cases,
successfully decode, yielding incorrect results. See
#97 and
#101.

Performance improvement of the ‘Peek’ monad, by introducing more
strictness. This required a change to the internal API.

API and behavior of ‘Data.Store.Version’ changed. Previously, it
would check the version tag after decoding the contents. It now
also stores a magic Word32 tag at the beginning, so that it fails
more gracefully when decoding input that lacks encoded version
info.

0.4.0

Deprecated in favor of 0.4.1

0.3.1

Fix to derivation of primitive vectors, only relevant when built with
primitive-0.6.2.0 or later

Removes INLINE pragmas on the generic default methods. This
dramatically improves compilation time on recent GHC versions.
See #91.

Adds instance Contravariant Size

0.3

Uses store-core-0.3.*, which has support for alignment sensitive
architectures.

Adds support for streaming decode from file descriptor, not supported on
windows. As part of this addition, the API for “Data.Store.Streaming” has
changed.

0.2.1.2

Fixes a bug that could could result in attempting to malloc a negative
number of bytes when reading corrupted data.

0.2.1.1

Fixes a bug that could result in segfaults when reading corrupted data.

0.2.1.0

Release notes:

Adds experimental Data.Store.Version and deprecates Data.Store.TypeHash.
The new functionality is similar to TypeHash, but there are much fewer false
positives of hashes changing.

Other enhancements:

Now exports types related to generics

0.2.0.0

Release notes:

Core functionality split into store-core package

Breaking changes:

combineSize' renamed to combineSizeWith

Streaming support now prefixes each Message with a magic number, intended to
detect mis-alignment of data frames. This is worth the overhead, because
otherwise serialization errors could be more catastrophic - interpretting some
bytes as a length tag and attempting to consume many bytes from the source.